doubleheader Syllabification: (dou·ble·head·er)Pronunciation: /ˌdəbəlˈhedər/Definition of doubleheader noun 1a sporting event in which two games or contests are played in succession at the same venue, typically between the same teams or players. 2a train pulled by two locomotives coupled together. doubleheader in other Oxford dictionaries Definition of doubleheader in the British & World English dictionary